This invention relates generally to apparatus for straightening wire and, more particularly, to apparatus for straightening a length of wire which has been wound in a coil and which is to be cut into shorter pieces.
Even more specifically, the invention relates to wire straightening apparatus which, in general principle, is similar to that disclosed in Angstrom U.S. Pat. No. 293,212. In the apparatus of the Angstrom patent, wire is fed through a rotating mandrel or arbor having upstream and downstream straightening dies and having an intermediate straightening die located between the upstream and downstream dies. In order to control the angular bend or strain imparted to the wire as the wire threads through dies, the upstream and downstream dies are supported for selective axial adjustment toward and away from one another while the intermediate die is supported for selective adjustment radially of the upstream and downstream dies.
To the best of the present inventors' knowledge, wire straightening machines of the type disclosed in the Angstrom patent are not being--and may never have been-- used commercially by others. The inventors have recognized, however, that the principle taught by the Angstrom patent is superior to that incorporated in wire straightening machines which are in fact in present commercial use. In attempting to incorporate the Angstrom principle into a commercially viable machine, the inventors encountered a significant problem in that straightening dies of the type disclosed by Angstrom tend to wear quickly and thus experience an unacceptably short service life.